Implications of a suspicious afirma test result in thyroid fine‐needle aspiration cytology: An institutional experience

Abstract

BACKGROUND: Fine-needle aspiration (FNA) biopsy is the most frequently used method for thyroid nodule evaluation.However, up to 30% of cases are considered indeterminate. Surgery is typically recommended for these cases, but up to two-thirds of indeterminate cases are found to be benign. The Afirma test is used for the preoperative classification of thyroid nodules with indeterminate cytology. This study reviews the authors' institutional experience with Afirma. METHODS:A cohort of 132 cases of thyroid FNA with Afirma testing was selected from the study files and relevant information was recorded and analyzed. At the study institution, Afirma is mainly performed on atypia of undetermined significance (AUS)/follicular lesion of undetermined significance (FLUS) cases when diagnosed as such on repeat FNA. RESULTS:The cohort included 98 female (74%) and 34 male (26%) patients. Cytology diagnosis was AUS/FLUS in 68 cases (51.5%), follicular neoplasm (FN) in 39 cases (29.5%), and FN with oncocytic features (FNOF) in 25 cases (19.0%).Of the FNOF cases with suspicious Afirma findings, 2 (15%) were malignant and 11 (85%) were benign. Of the FN cases with suspicious Afirma findings, 9 (53%) were malignant and 8 (47%) were benign. Of the AUS/FLUS cases with suspicious Afirma findings, 10 (63%) were malignant and 6 (37%) were benign. CONCLUSIONS: The Afirma classifier is a useful

Noninvasive Follicular Variant of Papillary Thyroid Carcinoma and the Afirma Gene-Expression Classifier

“…Thus, more classical type PTCs are present in the SUS category than in the AUS/FLUS or SFN categories (19)(20)(21)(22)(23). Our findings are consistent with those reported by Lastra et al who found that of the malignant tumors resected at their institution with a suspicious Afirma result and a preceding AUS/FLUS or SFN diagnosis, 73% were FVPTCs (the FVPTCs were not further subclassified in this study), 14% were classical PTCs, and 14% were FTCs (24). Moreover, the finding that many of the carcinomas detected by the GEC are NFVPTCs is a direct reflection of the fact that the Bethesda categorization of a nodule is associated with tumor type, stage, and prognosis (22,25).…”

Molecular Testing of Thyroid Nodules: A Review of Current Available Tests for Fine-Needle Aspiration Specimens

“…There is a tendency for the Afirma GEC test to report a high percentage of benign Hürthle cell nodules as suspicious. 13,15,16,18,19 These studies indicate that the risk of malignancy for a suspicious Afirma result is lower for aspirates with Hürthle cell cytology (19%-23%) than for those without a prominent population of Hürthle cells.…”

European Thyroid Association Guidelines regarding Thyroid Nodule Molecular Fine-Needle Aspiration Cytology Diagnostics

“…In another single-center retrospective, unblinded study, Lastra et al [31] reported on the University of Pennsylvania experience, in which 132 cases of indeterminate cytology nodules were subject to GEC testing, including the categories of AUS/FLUS, FN, or FN with oncocytic features, with more than half of the cases being in the AUS/FLUS category (52%, 68/132). The prevalence of malignancy in the 50 cases in this study that had histopathological confirmation of diagnosis was 44% (22/50).…”

“…In summary, based on the above studies that reported on sensitivity and specificity, GEC test sensitivity was reported to range from 83 to 100% and specificity from 7 to 52%, whereas the prevalence of malignancy in histopathologically confirmed study populations ranged from 17 to 51% [10, 29-31]. …”

“…The prevalence of malignancy in the 50 cases in this study that had histopathological confirmation of diagnosis was 44% (22/50). In calculations using data from this study [31], the GEC test sensitivity was 100% (22/22) and specificity was 7% (2/28). No follow-up data were reported on patients who did not undergo surgery in this study.…”